Feeler device for copying milling machines



K. zwlcK Dec. 22, 1942.

FEELER DEVICE FOR COPYING MILL1NG`MACHINES Filed Jan. 27, 1958 2 Sheets-Sheet l Im/enfan- KURT Zwlfc Patented Dec. 22, 1942 FEELER DEVICE Fon corme luILLmG MACHINES l Kurt zwiek, Munich, Germany; vesiea'in. the Alien Propertyl Custodian Application January 21, 193s, serial No. 187,258

In Germany February5, 1937 1s claims.

This invention relates to a copying milling machine or machine for reproducing on one or more pieces of work stock the conguration of a pattern or sample. The reproduction maybe made i on the same scale as the pattern or sample or on a reduced Vor enlarged scale. I I

During the rough milling or cutting operation, while the work or reproduction is being milled to approximate size and before the final smooth i'lnishing thereof, it is desirable that the movements of the cutter be actuated by some kind of feeding means other than direct manual pressure, in order to save useless fatigue of the operator.

Such feeding` means may, for example, be inthe Y form of a manually driven screw feed, or may be driven by motor or power means of Iknown form.

The moldor patternto be copied lis frequently I made of soft or fragile material, or'has thin or narrow projecting parts which may be .easily broken by excessive pressure. It is desirable that some means be provided fornotifying the operator -when the -tracingstylus or feelingvme'mber comes. intojcontact with the pattern or mold, so that the voperator may stop the movement of the cutting tool and the tracing stylus in the direction in which they were previously being moved, to

avoid. damage to the pattern 'which might easily be caused by the heavy feeding force of manual screw feed means or of power feeding means,'and

which might even be caused undersome conditions by direct manual pressure.

It has heretofore been suggested that this notication to the operator be accomplished by electrical means. In one known form of device, the

tracing stylus is/displaced by contact with the I pattern and this closes an electric circuit to give an audible or visible signal to the operator. In

. another known form, the pattern is made of electrical conducting material and when the tracing stylus comes into contact with it a circuit is completed so that a signal is given. These prior known devices are not satisfactory, however, because they are cumbersome in use, and expensive to build and to keep in order, and because it is often diiilcult and expensive to make the pattern of electrical conducting material. Moreover, these prior arrangements have the grave disadvantage that they indicate to the operator merely the fact of engagementof the tracing stylus with Ithe pattern, Without giving any indication of the direction of the contact pressure,

or of the extent thereof.

Itl is an object of the present invention to provide a simple and inexpensive feeler device or tracing stylus assembly which will indicate to the of such a device which operates entirely through mechanical as distinguished from electrical parts and which requires no electrical circuit.V

- A further object is the provision of such a device of simple and compact form which can be readily substituted on existing copying or milling machines for `existing tracing stylus assemblies.

'I 'o these and other ends the invention resides incertain improvements and combinations of parts, all as will be hereinafter more fully described,.the novel features being pointed out in the claims at the end of the speciiicatiom In the drawings:

Fig. i is a diagrammatic plan of a typical copying milling machine with which the present invention maybe used;

Fig. 2 is a front elevation thereof;

Fig., 3 is' a vertical section through a' feeler device or tracing stylusassembly constructed in accordance with one embodiment of the present l invention;

Vof the device;

Fig. 5 is a plan view ofthe construction shown in Fig. 3, with .the mirror removed;

Fig. 6 is a view similar to Fig. 3 showing a modified form of construction, and

Fig. '7 is a. plan view of the construction shown in Fig. 6, .with the mirror removed.

The same reference numerals throughout,l the several views indicate the same parts. f

Referring now 'to Figs. l and 2 of the'drawings, there' is shown somewhat diagrammatically one of the many forms of copying milling machines with which the present invention may be used. 'I'he machine may include. .for example, a frame or standard II on which a member Il is vertically slidable, this member I I being suitably counterweighted to counterbalance all or any desired part ofthe weight of the /member I3 and other parts supported therefrom. A beam I5 is mounted on the member I3 for movement in the direction of the arms I'I of this the arms guiding the beam so that al1 positions thereof are parallel to each other. A second beam I9 isV mounted on the beam I5 for horizontal movement inA a directionrtransverse to the arms I'I. Thus the beam I9 is universally Inova-ble in all directions throughout the range of movement of the machine. It may move to left or right when-viewed as In Fig. 1,"by moving along its guideway on the beam I5., It may move toward and away from the frame or support I I by moving the beam I5 in the direction of the/arms I1. It may move upwardly and downwardly, or in a substantially vertical d1rec tion, by moving the member I3 upwardly and downwardly along its guideway on the frame I I.

The beam I9 carries two or more holders 2| and 23, one or more of which may hold a guiding or tracing stylus assembly, and one or more of which may hold a rotary cutting tool. If desired, the holders themselves may be of identical construction, and the tracing stylus assemblies and the cutting tool assemblies maybe of Y similar external form and dimensions, so that either the tracing stylus assembly or the cutting tool assembly can be placed, as desired, in any one of the holders. In the illustrative embodiment here shown, the holder 2| carries a tracing stylus assembly as will -be described in greater detail hereafter whilethe holder 23 carries a cutting tool assembly indicated in general at 21, this assembly having a cutting tool 29 rotated by any suitable means such as by the belt 3| driven in any known manner from a source of power such as an electric motor.

The machine also includes a frame part or standard 35 carrying a horizontal slide 31 movable in one-direction, which in turn carries another horizontal slide 39 movable in a direction transverse to the movement of the first slide, and this second slide 39v supports a table 4I on which may be mounted the model or pattern 43 to be copied, and-the work piece 45 on which a reproduction of the pattern is tobe made.

The mounting of the tracing stylusvand the cutting tool on the same beam, as here shown by way of example, is suitable for making a reproduction on the same scale. When the reproduction is to be made on a reduced or enlarged scale, then the movements of the beam may be controlled by a pantograph linkage of known form, in known manner, and the tracing stylus may be mounted on the pantograph linkage while the cutting tool is mounted on the beam, or vice versa, or again, both the tracing stylus and the cutting tool may be mounted on different parts of any suitable pantograph iinkage. The tracing stylus assembly of the present invention is not necessarily used on a beam, the beam arrangement here illustrated being shown simply by Way of example, and the tracing stylus assembly of the present invention is of general applicability whenever a tracing stylus is to be used in a copying milling machine or the like.

During the nal or finishing milling operation, it is usually preferred to operate the tracing stylus over the pattern by directhand pressure, applied either directly to the stylus or to the beam or pantograph linkage on which it is mounted. During the earlier rough cutting or milling operation, however, much useless fatigue of `the operator can be avoided if feeding means is provided for moving the stylus and the cutter over the pattern and the work, respectively, without the necessity of direct hand pressure This rough milling may be accomplished by holding the beam I9 stationary and by moving the pattern and the work relatively to the stylus and cutter by operating the screw feeds controlling the slides 31 and 39,`but preferably it is accomplished by leaving thetable 4| stationary and providing suitable feeding means for moving the beam |9. For example, the frame II may be provided with a forward extension 5| on which is mounted a horizontal slide A53 movable in a direction from front to back of the machine, its movement being controlled by the screw feed 55. On this slide 53 is a second horizontal slide 51 movable in a direction transverse to the slide 53 and controlled by the screw feed 59. The slide 51 is connected as by means of a link 6I to some suitable part of the beam I9 or of theautting tool assembly 21,. so that movements of the slide 51 are imparted to the beam and thus to the tracing stylus and the cutting tool, the connection being such that the beam I9 may move vertically independentlyof the connection 6I.

If desired, a power feed of any suitable known form may be substituted for the hand rscrew feeds 55 and 59. The extension 5| on the frame may carry an electric motor 63 to drive either the cutting tool, or the power feeds, or both.

During the rough cutting operation, the operator moves the beam I 9 by means of the hand or power feeds, rather than by direct'hand'pressure. This not only saves much energy on the part of the operator, but also avoids subjecting his hand to the effect of such vibration as may be present in the beam I9 and associated parts. During the movementsV of the beam I9 by the feeding means, however, it is important that he be able to ascertain quickly and easily whether or not the tracing stylus-is in Contact with the pattern or model, so that he may continue the feeding movement in the same direction if the stylus is not yet in contact with the pattern, or may discontinue ythe feeding movement before breakage or damage to the pattern results, if the tracing stylus has come into contact therewith. When the stylus has come into contact with the pattern, it is also important for the operator toknow the direction of the contacting pressure between the stylus and the pattern, in order that he may know vin which direction he should operate the feeding means. When the stylus and cutting ktool are moved by hand or power feeding 'means rather than by direct hand pressure, the sense of touch cannot be relied upon to inform the operator accurately of the fact of contact or oi' the direction or extent of the contacting pressure. The knowledge of 'these important factors is readily communicated to the operator by means of the improved tracing stylus assembly of the present invention, now to be described. l Referring now to Figs. 3, 4, and 5 oi the drawings, the `assembly includes a main outer sleeve or tube 1I secured in any suitable manner in the holder in which the stylus is to be mounted, such as the holder 2| on the beam I 9. A second sleeve 13 is mounted in the sleeve 1I and projects below the lower end thereof. The tracing stylus itself,` indicated at 15, is of any suitable orm or shape` depending on the requirements of the work or of the pattern, and is inserted in 'a sleeve 11, the lower end of which is longitudinally slotted at 19 and on which is screwed a clamping nut 9| having a conical or tapered portion so that lwhen i other tracing stylus of different shape or form may be substituted.

The sleeve 11 is provided with a spherical zone which is seated on a spherical zone seat at the lowerend of the sleeve 13, and held thereon by a nut 81, so that the parts constitute ineflect a ball and socket joint, by means of whlchthe sleeve 11 and tracing stylus4 15 may tilt in any direction relatively to the sleeves 1I and 13, about the center ofv rotation indicated at 89. The up- 4 per part of the sleeve 11, above the ball and socket joint, is somewhat smaller than the internal diameter of the sleeve 13, so that limited tilting movement of th'e sleeve 'l1 in the sleeveA 13 is possible, the extent of such movement being limited by an inwardly projecting annular shoulder 9| on the sleeve 13 near theupper end of the sleeve 11.

Around the upper reduced end of the sleeve 11 are arranged a series of radially extending spring plunger holders 93, each having, as shown in Fig. 4, a spring plunger 95 pressed radially inwardly by a spring 91. These various plungers act upon the upper reduced end of the sleeve 11 to hold this sleeve normally in a central position in the sleeve 13, but pressure in any lateral direction on th'e lower end of the tracing stylus 13 is able to move/the upper end of the sleeve 11 in an opposite lateral direction, by compressing the springs 91 of the plungers on that side of the sleeve 1| toward which the sleeve 11 moves.

In the sleeve 1|, above the sleeve 13, is a sleeve IWI screwed into the upper end of the sleeve 13. Between the lower end of the sleeve IllI and a suitable shoulder on the sleeve 13 are a pair of transverse plates |03 having alined v apertures substantially at their centers, formed to provide a seat for a spherical ball |05 secured to a vertical rod |01, to form a ball and socket joint s that the rod |01 may tilt in any lateral direction. The lower end of the rod |01 is somewhatl enlarged or made with an approximately spherical ball, and fits with close clearance into abushing |09 mounted tightly in the upper end of the sleeve 11. The upper end of the rod |01 above the ball`| is much longer than the lower end below the ball and the upper end terminates at II3 just beneath a transparent top plate or ycover plate II5 (such as a plate of glass) closing the upper end of the sleeve |0I. I

When the lower end of the stylus 15 is deected laterally in any direction by contact with the pattern, this will cause corresponding movement of the upper end of the sleeve 11 and of the bushing |09, which will move the short lower end of the rod |01 and cause a corresponding but greatly magnified deflection of the upper end II3 of the rod. Although the permissible lateral deflection of the lower end of the tracing stylus 15, as limited by the shoulder 9|, is off very small extent, the magnifying or leverage effect caused by the great length of the upper arm of the rod |01 in comparison to the lower arm thereof, results in a large and readily observable lateral deilection of the upper end I I3 of the rod |01. It is apparent that the direction in which the upper end I I3 will be deflected from its normal central position, will be thesame as the direction of deiiection of the lower end of the tracing stylus 15. Thus the operator, by observing the upper end I I3, will be notied notonly of the fact that the tracing stylus is in contact with the pattern, but also of the direction of the contacting pressure, and he can observe the degree 0r magnitude of the contacting pressurey by observing the extent to which the upper end |I3 has been deected from its normal central position.

' To aid the operator in observing the conditions, the upper end II3 of the rod |01 is preferably very brightly colored in order to be'easlly observable, and the transparent plate I I5 is preferably provided with a series of suitable reference marks or graduations, such for example, as a series of circles |2|, |23, and |25 concentric with each' other and with the normal undisplaced position of the upper end I I3 of the rod |01. When the upper end of the rod is in normal or central position, it is centrally located with respect to the concentric circular markings, as indicated in Fig. 5. vThe circles V|2| and |23 may indicate between them the zone to which thek end IIS should be deflected in any direction when the stylus is contacting with the pattern with' the l normal proper degree of pressure to complete or ilnish the rough cutting of the work. That is, when the'end |I3 is deflected to a position between the circles |2| and |23, this indicates the correct deflection of the tracing stylus which corresponds to the working clearance lor allowance customary when completing a rough cutting or rough' milling operation. When the end I|3 y these circles.

is deflected beyond the circle |23, to the Aposition of the circle |25, for example, then the operator knows that the tracing stylus is pressingV too heavily against the pattern and that the cutting tool may be cutting too deeply or beyond the clearance or allowance 'permissible for the rough cutting operation. Similar1y,if the end ||3 is visible within the circle I2 I, the operator knows that the stylus is not yet pressing against the pattern hard enough to produce the correct" deflection, and further pressure is needed before the rough cutting operation is completed Y.

Il. desired, the annular space between the normal or correct circles |2I and |23 may be shaded, or rendered opaque, or otherwise suitably treated to emphasize the zone defined by If this zone be rendered opaque, then when the end I |3 is deflected to the normal or correct extent, it will be beneath this opaque zone and will not be visible, so that whenever the end v I |3 is visible the operator will know that it `is deflected either too much or too little for proper completion of the rough cutting operation.

If the 'upper end of the tracing stylus assembly is too high for the operator `to look downwardly upon it conveniently, or if it is 'otherwise placed in a location where it is inconvenient fuor the operator to see it, one or more mirrors may be arranged at an angle over the transparent plate I|5, as indicated diagrammatically at |21, so that thevoperator may readily observe conditions by looking at the mirror.

The' above described arrangement is of great advantage in copying relief patterns, that is,`

. patterns having thr'ee dimensional surfaces, and

is a great aid not only in assuring proper conformance-between the work and the pattern at .the end of the rough cutting operation,.but also in preventing excessive lateral pressure of the stylusragainst the pattern, which might break off small projecting part-s of the pattern. It is seen that this arrangement notifies the operator not only of the fact of engagement of the stylus with the pattern, but also of the direction of the engaging pressure, and of the degree or magnitude of such pressure, the latter two of these'indications being of great value to the operator in properlyoperating the copying machine.

The tracing stylus assembly of the form described above is especiallyusuitable for giving indications where the stylus comes into lateral Contact with upwardly projecting parts of the theoperator an indication of vertical contact or pressure between thestylus and the pattern, instead of merely lateral conta-ctV orpressureas inthe form -iust described. The assembly may K thenbe constructed as disclosed in Figs. 6 and 7,

in ,which the sleeve 11 which carries the tracing stylus- 15,1. instead of being mounted with a ball and socket jointpdirectly in the lower "end of the sleeve 13; is mounted with a ball and -socket joint at the lower ed of a sleevev |3|slidable vertically in the sleeve 13 and constantly pressed downwardly by a coiled spring |33. Radial studs |35 mounted in and. spaced circumferentially around the sleeve 13 have inner ends projecting into vertical s lots in the sleeve |3|, and prevent the sleeve from dropping downwardly out of the sleeve 13, also limiting upward movement oi' the sleeve when upward pressure is exerted on the lower end of the stylus 15. 'I'he annular shoulder 9| which limits the lateral deilection of the upper end of the sleeve 11 is mounted on the upper end of the sleeve |3| instead of on the sleeve 13.

A pin |31 slidable vertically through the partition plates |03 and spaced from the rod |01, rests' which swings back and forth close to one side of the space within the sleeve ||I|, and out of the way of deiiection oi' the upper end 3 of the rod Downward pressure of the tracing stylus assembly on the pattern will compress the spring |33 and cause upward deection of the stylus and of the parts 11 and |3|, which will raise the pin |31 and swing the upper end of the bell crank arm through a greatly magniiled extent because of the leverage eiiect. -By observing the position of the upper end of the arm |45, the operator will i be notified not only-oi! thefact of vertical engagement of the stylus with the pattern, but also of the extent or magnitude of the engaging pressure, and this will not interfere in any way with the lateral deflection oi' the tracing stylus and the indication thereof by the upper. end i3 of rod I0 The transparent plate ||5 may be provided with suitable markings or graduations to cooperate with the upper end of the arm I 45, in a manner similar to the markings |2'|, |23, and |25 above described. For example, as shown in Fig. '1 the plate ||5 may have lines marking out the zone along which the arm |45 sweeps, and cross lines |5|, |53, and |55 similar to the lines |2|, i23, and

|25. The lines |5i and |53 may indicate between them the normal or "correct" extent oi deidentical with that described in connection with Figs. 3, 4 and 5, and the same reference numerals used in'Figs. 3, 4, and 5 have been employed'to denote the corresponding parts in Figs. 6 and 7,

which need not be furtherdescribed. e

While certain embodiments of the invention have been disclosed, it is to be understood that the inventive idea may be carried out in a number of ways. This application is thereforenot to be limited to the precise details described, butbis intended to cover all variations and modica-v tions thereof falling within the spiritof the invention or the scope of the appended claims.v

I claim:

1. A copying machine including stylus Vholding Y means, a tracing stylus mounted in said holding means and movable bodily Yover a pattern, said stylus being displaceable relatively to-said hold" ing means through a limited range, resilient means tending to maintain said stylus in normal undisplaced position relatively to saidholding tool operatively connected to said stylus for coraV responding movement Vover work.

2. A tracing stylus assembly for use on copying machines and the like, said assembly including hollow body means, a stylus'holder mounted in said body means for-limited movement rela- Y' tive thereto, said holder being arranged to receive a stylus in one end, the other 'end of. said holder having an opening therein, and indicating means including a rod mounted in said body means.V

and having one end engaged in said opening in said stylus'holdenand means fulcruming said rod near said end thereofyso thatwhen said stylus holder moves laterally relative to's'aid 'body means, it will cause lateral displacement of said end of said rod and magniiled lateral movement Y of the remote end of said rod. Y

3. A tracing stylus assembly for use on copying machines and the like, said assembly includin'g body means, a stylus mounted on saidbody means for limited movement relative theretoin any direction in one plane from a central position, resilient means tending to hold said stylus in said central positive relative to said body means and tending to resist displacement from said position, and Vpointer means pivotally mounted on said body means, said pointer means including a lever mounted for universal movement in any direction in one plane and having a short arm operatively connected to said stylus to be moved when said stylus is displaced trom said position and having a longer arm moved by said short arm to'give a magnied indication' of the direction and'extent of said displacement of said lstylus. f

4. A tracing stylus assembly i'or use on copying machines and the like, said assembly including body means, a stylus mounted on 'said body means for limited movement relative thereto? y both laterally and longitudinally, means tending Y to hold said stylus in a predetermined undis-A placed positionl relative to said body means, pointer means including a movement magnifying lever for indicating lateral displacement of said stylus relative to said body means, and other pointerY means including a movement' magnifying lever `for indicating longitudinal .displacement of, said stylus relative to said body means.

V5. A tracing stylus assembly for use on copying machines and the like, said assembly including bodyy means, a stylus mounted-on said bodyV means for limited movement relative thereto in any direction in one plane from a central position, means tending to hold said stylus in said central position relative to said body means.. said body means including a transparent-member, and pointer means including a lever mounted Afor universal movement in any direction in one 6. A construction as described in claim 5, fur- 4 ther including a ring marked on said transparent member approximately concentric with the apparent position of said pointer means when said stylus is in said central position, to serve as a reference marking to indicate when said stylus is displaced to a normal Yextent from said undisplaced position.

7. A construction as described in claim 5, furpointer means as seen through said transparent member.

8. A tracing stylus assembly for use oncopying machines and the like, said assembly including upright hollow tubular body means, a stylus s mounted in and projecting downwardly below said body means for hunted movement relative thereto, pointer means including an upright rod pivotally mounted within said hollow body means and operatively connected near its .lower end to said stylus for mechanically indicating the movements thereof relative to said body means by lateral displacement of the upper end of said rod, and mirror means mounted on said body means adjacent the upper end thereof for reflecting an image of the upper end of said pointer means in a lateral direction, so that the position of said pointer means may beV readily observed by an operator stationed laterallyaway from said tracing stylus assembly.

9. A tracing stylus assembly for use on copying machines and the like, said assembly includ-- ing a body, a stylus member pivotally mounted on said body for tilting movement in any direc- 4 10. A construction as described in claim 9, in

which said movable indicating member -is in the form of a lever separate from said stylus member and mounted for tiltingv movement in any direction about a point intermediate its ends andhaving one short arm connected to said stylus member and onevarm of much vgreater length with its end adjacent said reference mark,

for giving a substantially magnified indication -of the extent of stylusV tilting movement.

l11. A tracing stylus assembly for use on copying machines and the like, said assembly including a tubular body, a stylus member mounted on said body for endwise movement relative to said body and carryingv a stylus projecting from one` end of said body, spring means within saidA body tending to move said stylus member outwardly with respect to said body, a plate lof atleast partially transparent material extending acros'sV andV substantially closing the opposite end of said body, a reference mark on said plate, anda movable'indicating member in the form of a lever f separate rom'said stylus memberandpivotally Ymountedwithin said tubular body and having one relatively short arm acted upon and moved by endwise movement of said stylus member and one arm of much greater length with its end adjacent said reference mark and movable relatively to said reference mark for mechanically giving, by its position with. respect to said reference mark, a substantially magniedvisual indication of the extent of endwise stylus movement.

12. A copying machine including a tracing stylus for movement over a pattern, a cutting tool operatively connected to said stylus for corresponding movement over work, said stylus being mounted for lateralmovement universally in any lateral direction, and means including a lever coupled to said stylus and mounted for limited tilting movement in any direction about a fulcrum remote from said stylus, for indicating the vdirection of contacting pressure between the stylus and the pattern.

13. A copying machine including atracing stylusfor movement over a pattern, a cutting tool operatively connected to said stylus for corresponding movement over work, said stylus being mounted for lateral movement universally in any lateral direction, and mechanical means including a lever coupled to said stylus and mounted for limited tilting movement in any direction about a` ulcrum remote from said stylus, for giving a visual indication of the di rection of contacting pressure between the stylus and the pattern directly by visual observation of thedirection of movement ofa predetermined portion of said lever.

14. A tracing stylus assembly for use on copying machines and the like, said assembly including a tracing stylus for movement over a pattern, said stylus being mounted for limited tilting movement in any direction about a fulcrum intermediate its ends, and means including a` lever coupled to said stylus and mounted for limited tilting movement in any direction about a fulcrum remote from the fulcrum Aof said stylus for indicating both the direction and the magnitude of contacting pressure between the stylus and thepattern directly by visual observation of thel direction and extent of movement of a predetermined portion of said lever. a 15. A tracing stylus assembly for use on copylng machines and the like, said assembly including body means of approximately'hollow cylindrical form, a stylus mounted on said body means and plvoted about a fulcrum near one end of said body meansfor' limited lateral tilting movemerit in any direction relative thereto, and indicating means in the form of a lever mounted in said hollow body means for lateral tilting movement in any direction about a fulcrum intermediate the ends of said lever and remote from the fulcruni of said stylus, one end of said -lever being operatively coupled to said stylus to body meansLa stylus as-V intermediate its ends for limited lateral tilting movement in any direction relative to said body means, pointer means including an upright rod pivotally mountedl within said hollow `body` means for limited lateral tilting movement in any direction about a. fulcrum intermediate its ends, said pointer means beingoperatively oonnected near its lower end to said stylus assembly for indicating the movementsthereof relative to said body .means by lateral displacement oi' the upper end of said rod, and mirror means mounted on said body means adjacent th'e upper Aend thereof for reflecting an imagejof the upper end oi said rod in a lateral direction so that the position oi' said upperfend' of said rod may be readily observed byan operator stationed laterg ally away from said tracing sty us unit.

zum' 

